Fuel is Destroying Your Two Cycle Equipment
The landscape business depends on hand held equipment. The gold standard for power and reliability combined with lightweight and ease of operation is the two-cycle engine. However, the fuel available today at the pump is wreaking havoc for operators, owners, and most significantly repair technicians; costing time, money, and decimating profits for professional users.
According to Pete Fernald, Technical Services Manager for Maruyama “Fully 75% or more of all two cycle engine repairs are directly caused by fuel related issues.” Fernald goes on to say that these issues can be caused by the use of:
- Improper Oil Ratio Mixtures
- Old Fuel
- Ethanol in the fuel
Proper Oil Mixture Ratios
Virtually all of today’s two-cycle engines operate on a fuel to oil mix ratio of 50:1. That translates to 2.6 ounces of oil for every gallon of gasoline. It is very important to properly mix fuel to oil. New, modern, EPA compliant two-cycle engines are very sensitive to fuel to oil mixtures. Counter-intuitively, mixing too much oil is actually worse than mixing slightly less than optimal amounts of oil. Richer oil mixtures actually cause residual petroleum compounds to build up in the ring lands resulting in ring seizure and engine failure.
Fuel to oil mixtures are often dictated by the size fuel container being used. Oil packaging is sized to match the most commonly available fuel container sizes.
| Container Size |
Fuel in Gallons |
Oil in Ounces |
| 1 Gallon |
1 Gallon |
2.6 Ounces |
| 2 Gallon |
2 Gallons |
5.2 Ounces |
| 2.5 Gallons |
2.5 Gallons |
6.4 Ounces |
| 5 Gallons |
5 Gallons |
12.8 Ounces |
Recently, there has been a shift in fuel container sizes available in stores from the most commonly purchased 2.5 gallon container down to a 2 gallon container. This presents a significant problem when mixing fuel and oil because the tendancy is to use a 6.4 ounce, 2.5 gallon oil bottle with the 2 gallon can. However, the result of such a mix is to have a 40:1 mixture of fuel to oil. This can result in severe engine damage and dramatically shortened engine life spans, often times cutting and engine’s life span from more than 1500 operating hours to less than a few hours!
Be extra vigilant when mixing fuel to oil for your two cycle engines. Remember, more oil than required is NOT beneficial to your engine, but rather detrimental.
The Impact Of Old Fuel
Today’s gasoline is not a single compound, but rather a highly complex blend of more than two hundred, to as many as five hundred different hydro-carbons. This mixture of compounds is not shelf (or rather fuel container) stable for a long period of time without the addition of a significant fuel stabilizer such as Sta-bil, or the use of a premium two cycle mixing oil like Maruyama XD Extreme Duty Two Cycle Mix Oil. Without the addition of one of these compounds, the fuel quickly begins to lose volatility. This translates to a loss of power in your engine, and harder starting, as well as gum and varnish buildups in the fuel system
The best practice is to mix only enough fuel for NO MORE THAN one or two days use at a time. Even with the addition of fuel stabilizers, the best idea is to use your two-cycle fuel quickly for optimal performance.
The Impact of Ethanol in Fuel
The most problematic fuel related issues in the two-cycle engine space today are those issues relating to the use of ethanol as a motor fuel. For the past several years ethanol has been touted as the fuel of the future for the United States. While this debate continues at many levels of government and while litigation winds it’s way through the court systems; the two-cycle engine industry contends with the serious fall out of ethanol as a fuel.
Ethanol causes two-cycle engine trouble in many ways, including:
- Degreasing and delubricating of engines.
- Attacking and degrading soft components of engines.
- Enleaning the fuel:air mixture.
- Decreasing engine power
- Water damage to engines
Ethanol is added to fuel primarily as an oxygenating compound. In fact, while straight run gasoline contains 0% oxygen, Ethanol contains 37% oxygen as part of it’s chemical foundation. Translated to the impact on your equipment, ethanol fuels with 10% ethanol concentrations result in a 4% increase in oxygen to the fuel:air mixture. This is the same net effect as leaning out the carburetor.
Ethanol is an excellent solvent. It dissolves grease, oil, and it attacks soft compounds like plastic, rubber, and aluminum. The problem is that two-cycle engines depend on mix oil for lubrication while the ethanol in fuels attempts to delubricate the engine. The solvent properties of ethanol cause damage to the plastic and rubber components of the fuel system, and in fact attack the aluminum structure of the engine itself over time. In fact, ethanol attacks virtually every component of a two cycle engine causing major and potentially engine killing damage along the way.
Ethanol is Hygroscopic
Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment. Ethanol claims moisture from the air, and the result is that ethanol, left to sit for a period of time, gathers moisture into water, and if subsequently used as fuel robs the engine of power, and causes damage to the fuel system due to gum and varnish deposits.
Left to sit for a relatively short period of time, the ethanol in fuel will bond to water in the atmosphere and leave a layer of water in the fuel container. This process, called phase separation, results in water buildup in the fuel container.
Water-bearing ethanol fuel also causes internal engine damage due to improper combustion, and can result in dangerous temperature spikes of the exhaust system as the un-combusted fuel mixture reaches the heated catalyst of the exhaust system.
The threat of damage to two-cycle engines from ethanol is very serious and in fact is the number one cause of engine damage today in the two-cycle world.
Best Practices For Fuel In The Two-Cycle Industry
According to Pete Fernald, Technical Service Manager at Maruyama, here are some “Best Practices” that will result in a reduction in fuel related issues and repairs.
- When possible, purchase fuels that contain NO ethanol.
- Mix fuel to oil very carefully. Always insure that you maintain a 50:1 mix ratio.
- Never mix oil to a “Richer” ratio than manufacturer recommendations.
- Mix only enough fuel to last one or two days at a time.
- Always have the same person on your crew mix your fuel:oil mixtures.
- Purchase fuels only from high volume, reputable retailers.
- Store your machines with the fuel tank at 95% of capacity to reduce the introduction of atmospheric moisture into the fuel system.
- Always use a fuel stabilizing additive like Sta-Bil or Maruyama XD Two Cycle oil.
- When in doubt, dispose of your older fuel and start over with fresh fuel and a fresh oil mix.
These practices, along with regular professional maintenance of your equipment can dramatically reduce your labor and repair costs, and increase the dollars posted to your bottom line.